Win_Strain was a program developed from the strain program of Ohashi, previously published in the book Comparative Crystal Chemistry by Hazen and Finger. It calculates the strain between two sets of unit-cell parameters. This is essential for interpreting changes in unit-cell parameters with changes in temperature, pressure or composition, or for calculating the components of the spontaneous strain arising from a phase transition. When the components of the strain tensor are normalised by the temperature or pressure change, the thermal expansion and compressibility tensors are obtained.

The 2019 release of EosFit-7c includes calculations of strain, compressibility and expansion tensors, with all of the options that were included in the Win-strain program for axial conventions and strain types. For crystals of monoclinic or triclinic symmetry the orientation of the principal axes of strain with respect to both the Cartesian axial system and the crystallographic axes is also calculated. This is also the orientation of the strain ellipsoid and strain quadric representations of the strain. The strain utility in EosFit-7c has improved algorithms to solve the Eigenvalue problems and is therefore more robust than Win-strain when Eigenvalues of the strain are accidentally equal.

Win_Strain is still available for Download, but is no longer supported. The zip archive includes the program, the users guide and example datafiles. Extract the pdf file of the manual which contains further installation instructions.